The present invention relates to a method, for mounting an injection pump on an internal combustion engine and also to a multiple-cylinder and single cylinder internal combustion engine with plug-in pumps which are mounted in accordance with the method according to the invention.
Single-cylinder plug-in fuel injection pumps, called plug-in pumps for the sake of brevity, are always used to advantage when the expense for a single row or distributor injection pump in engines with low cylinder output (approximately 2 to 30 KW/cyl.) is too great and when the injection pumps are to be mounted as close as possible to the injection nozzle of the respective engine cylinder because of the use of shorter compression lines and the improved injection conditions which can be achieved accordingly. Plug-in pumps do not have their own drive, but are driven by a camshaft belonging to the engine. The injection rate is regulated by way of a control rod of the engine which, like the feed quantity adjusting element of the plug-in pump, lies beneath the respective fastening flange within the pump installation bore of the internal combustion engine.
Pumps of this constructional type are known, for example, from the firm Robert Bosch GmbH, Stuttgart, by the designation PF 1Q . . . and PFR 1K . . . (e.g., see the publication "Injection Equipment for Diesel Engines with PF Injection Pumps"; VDT-UBP 001/6 by Robert Bosch GmbH, Stuttgart), and before being mounted on the internal combustion engine each of these pumps is adjusted to a desired feed quantity, which is the same for all pumps of the same series, on a test bench accompanied by the use of a test base and is inserted and fastened in the respective pump installation bore of the internal combustion engine with the assistance of an adjusting arrangement. Since the adjusting arrangement,which is provided with a positioning peg, only fixes the aforementioned pumps in their mounting position at the pump installation bore, the engine must be accurately adjusted again on the test stand with respect to the feed quantities of the individual plug-in pumps in a very costly manner. In so doing, adjustable coupling parts of the control rod belonging to the engine must be coupled with and adjusted to the feed quantity adjusting elements of the plug-in pumps. This testing process must be performed again when replacing an individual pump.
A method of the type according to the generic part of the claim is known from EP-ES No. 0 090 226 which avoids the disadvantages referred to and which guarantees a feed rate which is the same for all plug-in pumps of an internal combustion engine when the plug-in pumps are installed in the internal combustion engine. Thus, for the first time, with desired feed quantities guaranteed by the injection pump manufacturer, this method ensures a uniform feed to all plug-in pumps in multiple-cylinder internal combustion engines, also without subsequent adjustment of the engine. The control rod belonging to the engine can be constructed as a simple stamped sheet metal part with fixed counter-coupling parts for the coupling parts of the feed quantity adjusting elements of the plug-in pumps and the internal combustion engine also no longer needs a viewing window for readjusting the control rod. Also, the engine need no longer be put on the test stand in order to adjust the required engine output, which is especially advantageous in an integrated drive, since, for instance, there is no longer any possibility of adjusting the engine with respect to its output along in a unit which is mounted in a fixed manner on the engine crankshaft. The substantial characteristic features of this method consist in that a first adjusting aid of an adjusting arrangement, e.g. a benchmark, is arranged at the fastening flange of the plug-in pump before the plug-in pump is mounted by means of an apparatus located on the test base and a second adjusting aid, e.g. also a benchmark, of the adjusting arrangement at the pump installation bore of the internal combustion engine is arranged in each instance in a position assigned to the basic testing position of the feed quantity adjusting element at the internal combustion engine by means of a pump dummy when the control rod belonging to the engine is blocked in the basic testing position. When the plug-in pump is inserted in the pump installation bore the two adjusting means are then made to overlap each other. The adjusting means used and indicated in the known method, e.g. benchmarks or hole and pin plug-in connections, are immovably fixed after being attached and can no longer be corrected. In the event of an unintentional faulty adjustment or in case of repairs to some structural component part, this leads to costly subsequent work or the necessity of exchanging important structural component parts.